Spin interference in silicon one-dimensional rings

We present the first findings of the spin transistor effect in a Rashba gate-controlled ring embedded in a p-type self-assembled silicon quantum well that is prepared on an n-type Si(100) surface. The coherence and phase sensitivity of the spin-dependent transport of holes are studied by varying the values of the external magnetic field and the bias voltage that are applied perpendicularly to the plane of the double-slit ring. First, the amplitude and phase sensitivity of the 0.7 × (2e²/h) feature of the hole quantum conductance staircase revealed by the quantum point contact inserted in one of the arms of the double-slit ring are found to result from the interplay of the spontaneous spin polarization and the Rashba spin-orbit interaction. Second, the quantum scatterers connected to two one-dimensional leads and the quantum point contact inserted are shown to define the amplitude and the phase of the Aharonov-Bohm and the Aharonov-Casher conductance oscillations.